Abstract:

A hydroisomerization catalyst of the present invention is obtained by
calcining a catalyst composition containing an ion-exchanged molecular
sieve or a calcined product thereof, and at least one metal selected from
the group consisting of metals of Groups 8 to 10 in Periodic Table of the
elements, molybdenum and tungsten, carried on the ion-exchanged molecular
sieve or the calcined product thereof, wherein the ion-exchanged
molecular sieve is obtained by ion-exchanging a molecular sieve, which
includes nanocrystals having a pore structure of ten-membered rings or
eight-membered rings and having a ratio of the pore volume to the
external surface area ([pore volume]/[external surface area]) of
2.0×10-4 mL/m2 to 8.0×10-4 mL/m2 and
contains an organic template, in a solution containing a cationic
species.

Claims:

1. A hydroisomerization catalyst, obtained by calcining a catalyst
composition comprising:an ion-exchanged molecular sieve or a calcined
product thereof, the ion-exchanged molecular sieve being obtained by
ion-exchanging a molecular sieve in a solution containing a cationic
species, the molecular sieve comprising: a nanocrystal having a pore
structure of ten-membered rings or eight-membered rings and having a
ratio of the pore volume to the external surface area ([pore
volume]/[external surface area]) of 2.0.times.10.sup.-4 mL/m2 to
8.0.times.10.sup.-4 mL/m2; and an organic template; andat least one
metal selected from the group consisting of metals of Groups 8 to 10 in
Periodic Table of the elements, molybdenum and tungsten, carried on the
ion-exchanged molecular sieve or the calcined product thereof.

2. The hydroisomerization catalyst according to claim 1, wherein the
molecular sieve comprising an organic template is ZSM-22, ZSM-23, or
ZSM-48 type zeolite.

3. The hydroisomerization catalyst according to claim 1, wherein the
ion-exchanged molecular sieve is an ion-exchanged molecular sieve
obtained by ion-exchanging the molecular sieve comprising an organic
template in the presence of ammonium ions or protons.

4. The hydroisomerization catalyst according to claim 1, wherein the
ion-exchanged molecular sieve is an ion-exchanged molecular sieve
obtained by ion-exchanging the molecular sieve comprising an organic
template in a solution containing water as a main solvent and a cationic
species.

5. The hydroisomerization catalyst according to claim 1, wherein the
ion-exchanged molecular sieve is an ion-exchanged molecular sieve
obtained by ion-exchanging the molecular sieve comprising an organic
template by replacing the solution with a new one once or more.

7. The hydroisomerization catalyst according to claim 1, obtained by
calcining the catalyst composition in an atmosphere containing molecular
oxygen, and thereafter, reducing the calcined composition in an
atmosphere containing molecular hydrogen.

8. The hydroisomerization catalyst according to claim 1, wherein the
catalyst composition comprises 1 part by mass to 90 parts by mass of the
ion-exchanged molecular sieve or the calcined product thereof and 99
parts by mass to 10 parts by mass of at least one porous oxide selected
from the group consisting of alumina, silica, titania, boria, magnesia
and zirconia.

9. The hydroisomerization catalyst according to claim 1, wherein the
catalyst composition comprises:a carrier obtained by calcining a carrier
composition comprising 1 part by mass to 90 parts by mass of the
ion-exchanged molecular sieve and 99 parts by mass to 10 parts by mass of
at least one porous oxide selected from the group consisting of alumina,
silica, titania, boria, magnesia and zirconia; andthe metal carried on
the carrier.

10. A method of manufacturing a hydroisomerization catalyst, comprising:a
step a of hydrothermally synthesizing a molecular sieve comprising: a
nanocrystal having a pore structure of ten-membered rings or
eight-membered rings and having a ratio of the pore volume to the
external surface area ([pore volume]/[external surface area]) of
2.0.times.10.sup.-4 mL/m2 to 8.0.times.10.sup.-4 mL/m2; and an
organic template;a step b of ion-exchanging the molecular sieve
comprising an organic template in a solution containing a cationic
species to obtain an ion-exchanged molecular sieve;a step c of making the
ion-exchanged molecular sieve or a calcined product thereof carry at
least one metal selected from the group consisting of metals of Groups 8
to 10 in Periodic Table of the elements, molybdenum and tungsten to
obtain a catalyst composition; anda step d of calcining the catalyst
composition.

11. The method for manufacturing a hydroisomerization catalyst according
to claim 10, comprising, in the step c, making a carrier carry at least
one metal selected from the group consisting of metals of Groups 8 to 10
in Periodic Table of the elements, molybdenum and tungsten to obtain the
catalyst composition, the carrier being obtained by calcining a carrier
composition comprising 1 part by mass to 90 parts by mass of the
ion-exchanged molecular sieve and 99 parts by mass to 10 parts by mass of
at least one porous oxide selected from the group consisting of alumina,
silica, titania, boria, magnesia and zirconia.

12. A method for dewaxing a hydrocarbon oil, comprising bringing the
hydrocarbon oil containing normal paraffins having 10 or more carbon
atoms into contact with the hydroisomerization catalyst according to
claim 1 in the presence of hydrogen to convert a part of or the whole of
the normal paraffins into isoparaffins.

13. The method for dewaxing a hydrocarbon oil according to claim 12,
wherein the hydrocarbon oil is at least one selected from the group
consisting of slack wax, deoiled wax, paraffin wax, microcrystalline wax,
petrolatum, and wax from Fischer-Tropsch synthesis.

14. A method for manufacturing a lube-oil base oil, comprising a step of
bringing a hydrocarbon oil containing normal paraffins having 10 or more
carbon atoms into contact with the hydroisomerization catalyst according
to claim 1 in the presence of hydrogen under the condition of a
conversion of the normal paraffins of substantially 100% by mass, the
conversion being defined by the formula (I) described below:[Expression
1]Conversion of normal paraffins (%)=[1-(total mass % of normal paraffins
having Cn or more carbon atoms contained in a hydrocarbon oil after the
contact)/(total mass % of normal paraffins having Cn or more carbon atoms
contained in the hydrocarbon oil before the contact)]×100
(I)wherein Cn denotes a minimum number of carbon atoms of normal
paraffins having 10 or more carbon atoms contained in the hydrocarbon oil
before the contact.

Description:

TECHNICAL FIELD

[0001]The present invention relates to a novel hydroisomerization catalyst
and a method for manufacturing the catalyst, and a method for dewaxing a
hydrocarbon oil and a method for manufacturing a lube-oil base oil using
the hydroisomerization catalyst.

BACKGROUND ART

[0002]Among petroleum products, for example, lube-oils, gas oils and jet
fuels are products whose cold flow property is given importance to.
Therefore, base oils used in these products are desirably ones from which
wax components such as normal paraffins and slightly branched
isoparaffins causing reduction of cold flow property are completely or
partially removed, or in which the wax components are converted to
components other than the wax components. Hydrocarbons obtained by
Fischer-Tropsch synthesis method are recently paid attention as feedstock
oils when lube-oils and fuels are manufactured in view of containing no
environmental load substances such as sulfur compounds, but the
hydrocarbons also contain many wax components.

[0003]As a dewaxing technology to remove wax components from hydrocarbon
oils, for example, a method of extracting wax components with a solvent
such as liquefied propane or MEK is known. However, this method has such
problems that the operational cost is high, the applicable kind of
feedstock oil is limited, and further, the product yield is limited by
the kind of feedstock oil.

[0004]On the other hand, as a dewaxing technology to convert wax
components in hydrocarbon oils to non-wax components, for example,
catalytic dewaxing is known by which the hydrocarbon oil is brought into
contact with a so-called bifunctional catalyst having a
hydrogenation-dehydrogenation capability and an isomerization capability
to isomerize normal paraffins in the hydrocarbon to isoparaffins. As
bifunctional catalysts used for catalytic dewaxing, solid acids,
particularly catalysts containing a molecular sieve composed of zeolite
or the like and a metal of Group 8 to 10, or 6 of Periodic Table of the
elements, especially catalysts in which the molecular sieve carries the
metal, are known.

[0005]The catalytic dewaxing is effective as a method of improving the
cold flow property of hydrocarbon oils, but to obtain fractions suitable
for lube-oil base oils and fuel base oils, the conversion of normal
paraffins must be sufficiently high. However, since the catalysts used in
the catalytic dewaxing have an isomerization capability and also a
cracking capability of hydrocarbons, in the case where hydrocarbon oils
are catalytically dewaxed, a rise in the conversion of the normal
paraffins involves progress of turning the hydrocarbon oils into light
oils, bringing about a difficulty of obtaining desired fractions with a
high yield. Especially in the case where base oils for high-quality
lube-oils required to have a high viscosity index and a low pour point
are manufactured, it is very difficult to economically obtain target
fractions by catalytic dewaxing of hydrocarbon oils, and therefore,
synthetic base oils such as poly-α-olefins are often used in such a
field.

[0006]From the above situations, in the field of manufacturing lube-oil
base oils and fuel base oils, a catalytic dewaxing technology to obtain
desired isoparaffin fractions from hydrocarbon oils containing wax
components with a high yield is demanded.

[0007]Attempts have been made so far to improve the isomerization
selectivity of catalysts used in the catalytic dewaxing. For example,
Patent Document 1 described below discloses a process to manufacture a
dewaxed lube-oil by bringing a raw material of a straight-chain or
slightly branched hydrocarbon having 10 or more carbon atoms into contact
with a catalyst composed of a molecular sieve which has medium-sized
one-dimensional pores such as ZSM-22, ZSM-23 and ZSM-48 containing a
metal of Group VIII or the like in Periodic Table and whose crystallites
have a size not exceeding about 0.5 μm, under an isomerization
condition.

[0008]A molecular sieve constituting a catalyst for catalytic dewaxing is
usually manufactured by hydrothermal synthesis in the presence of an
organic template containing an amino group, an ammonium group or the like
to establish a predetermined pore structure. Then, the synthesized
molecular sieve is calcined at a temperature of, for example, about
550° C. or higher in an atmosphere containing molecular oxygen to
remove the contained organic template, for example, as described in the
final paragraph in section "2.1. Materials" on page 453 of Non-Patent
Document 1 shown below. Next, the calcined molecular sieve is typically
ion-exchanged into an ammonium type in an aqueous solution containing
ammonium ions, for example, as described in section "2.3. Catalytic
experiments" on page 453 of Non-Patent Document 1. On the molecular sieve
after the ion-exchange, a metal component of Groups 8 to 10 or the like
in Periodic Table of the elements is further carried. Then, the molecular
sieve on which the metal component is carried is dried, and filled in a
reactor, optionally through a process such as molding, and calcined
typically at a temperature of about 400° C. in an atmosphere
containing molecular oxygen, and further subjected to a reduction
treatment using hydrogen or the like at about the same temperature to
impart a catalytic activity as a bifunctional catalyst. [0009][Patent
Document 1] U.S. Pat. No. 5,282,958 [0010][Non-Patent Document 1] J. A.
Martens, et. al., J. Catal., 2006, 239, 451

DISCLOSURE OF THE INVENTION

[0011]Even by the manufacturing method described above in Patent Document
1, since the isomerization selectivity of a catalyst cannot be said to be
sufficient and the cracking activity is not sufficiently suppressed, it
is difficult to obtain, with a high yield, isoparaffin fractions suitable
for desired lube-oil base oils and fuel base oils from hydrocarbon oils
containing normal paraffin components. Especially in manufacture of base
oils of high-performance lube-oils, there is a need for raising the
conversion of normal paraffins to a degree that the base oils contain
substantially no normal paraffins. In this case, the cracking of normal
paraffins and/or isoparaffins being isomerized products become active,
and target isoparaffin fractions cannot be obtained with an economical
yield.

[0012]The present invention is achieved in consideration of the situations
described above, and has objects to provide a hydroisomerization catalyst
having a sufficiently low cracking activity of normal paraffins and/or
produced isoparaffins when the normal paraffin conversion is sufficiently
raised, and having a high isomerization selectivity, in
hydroisomerization of hydrocarbon oils containing normal paraffins, a
method for manufacturing the hydroisomerization catalyst, and a method
for dewaxing a hydrocarbon oil and a method for manufacturing a lube-oil
base oil using the hydroisomerization catalyst.

[0013]As a result of exhaustive studies to solve the above problems, the
present inventors have found that a catalyst manufactured by subjecting a
specified molecular sieve comprising a microcrystal having a specified
crystal morphology to an ion-exchange treatment in the state containing
an organic template to obtain an ion-exchanged molecular sieve, and by
making the obtained ion-exchanged molecular sieve carry a specified metal
exhibits a low cracking activity in a high conversion region of a normal
paraffin (normal decane) in the hydroisomerization reaction of the normal
paraffin, and can raise the yield of target isoparaffin fractions more
than the case where conventional catalysts are used, that is, the
catalyst simultaneously satisfies both a high isomerization activity and
a low cracking activity in high levels, and has a high isomerization
selectivity. This has led to the completion of the present invention.

[0014]The present inventors have studied microcrystals having the
specified crystal morphology described above from beforehand, and
reported that in Document "K. Hayasaka, et. al., Chemistry-A, European
Journal, 2007, 13, 10070-10077", a hydroisomerization catalyst in which
nanocrystals (nanorods) of ZSM-22 carry platinum has a lower activity
than a hydroisomerization catalyst in which ZSM-22 having usually-sized
crystals carry platinum. However, subjecting such nanocrystals to a
specified ion-exchange treatment described above improves the
isomerization selectivity in a high conversion region, which was an
unexpected result.

[0015]The hydroisomerization catalyst of the present invention is
characterized that the hydroisomerization catalyst is obtained by
calcining a catalyst composition comprising an ion-exchanged molecular
sieve or a calcined product thereof, and at least one metal selected from
the group consisting of metals of Groups 8 to 10 in Periodic Table of the
elements, molybdenum and tungsten, carried on the ion-exchanged molecular
sieve or the calcined product thereof, wherein the ion-exchanged
molecular sieve is obtained by ion-exchanging a molecular sieve, which
comprises a nanocrystal having a pore structure of ten-membered rings or
eight-membered rings and having a ratio of the pore volume to the
external surface area ([pore volume]/[external surface area]) of
2.0×10-4 mL/m2 to 8.0×10-4 mL/m2 and
comprises an organic template, in a solution containing a cationic
species.

[0016]Periodic Table of the elements used here indicates the long form
thereof prescribed by International Union of Pure and Applied Chemistry
(IUPAC).

[0017]The hydroisomerization catalyst of the present invention, in the
hydroisomerization of a hydrocarbon oil containing normal paraffins, can
sufficiently suppress the cracking of normal paraffins and/or produced
isoparaffins when the normal paraffin conversion is sufficiently raised,
and can develop a high isomerization selectivity. Use of the
hydroisomerization catalyst of the present invention for the
hydroisomerization of a hydrocarbon oil containing normal paraffin
components enables to obtain isoparaffin fractions suitable for desired
lube-oil base oils and fuel base oils with a high yield. Further, the
hydroisomerization catalyst of the present invention is useful especially
for manufacture of base oils of high-performance lube-oils.

[0018]In the hydroisomerization catalyst of the present invention, the
molecular sieve comprising an organic template is preferably ZSM-22
type-, ZSM-23 type-, or ZSM-48 type zeolite in view of the isomerization
activity and selectivity.

[0019]Further, the ion-exchanged molecular sieve is preferably one
obtained by ion-exchanging the molecular sieve comprising an organic
template in the presence of ammonium ions or protons in view of the
isomerization activity of the catalyst.

[0020]Further, the ion-exchanged molecular sieve is preferably one
obtained by ion-exchanging the molecular sieve comprising an organic
template in a solution containing water as a main solvent and a cationic
species in view of the efficiency of ion-exchange, and the like.

[0021]Further, the ion-exchanged molecular sieve is preferably one
obtained by ion-exchanging the molecular sieve comprising an organic
template by replacing the above-mentioned solution with a new one once or
more in view of the efficiency of ion-exchange, and the like.

[0022]Further, in the hydroisomerization catalyst of the present
invention, the catalyst composition preferably comprises platinum and/or
palladium carried on the ion-exchanged molecular sieve or a calcined
product thereof in view of the isomerization activity.

[0023]Further, the hydroisomerization catalyst of the present invention is
preferably one obtained by calcining the catalyst composition in an
atmosphere containing molecular oxygen, and thereafter, reducing the
calcined composition in an atmosphere containing molecular hydrogen.

[0024]Further, in the hydroisomerization catalyst of the present
invention, the catalyst composition comprises 1 part by mass to 90 parts
by mass of the ion-exchanged molecular sieve or the calcined product
thereof and 99 parts by mass to 10 parts by mass of at least one porous
oxide selected from the group consisting of alumina, silica, titania,
boria, magnesia and zirconia, in view that the desired isomerization
capability, and moldability and mechanical strengths of the catalyst
composition can easily be obtained.

[0025]Further, in the hydroisomerization catalyst of the present
invention, the catalyst composition preferably comprises a carrier
obtained by calcining a carrier composition comprising 1 part by mass to
90 parts by mass of the ion-exchanged molecular sieve and 99 parts by
mass to 10 parts by mass of at least one porous oxide selected from the
group consisting of alumina, silica, titania, boria, magnesia and
zirconia, and the above-mentioned metal carried on the carrier, in view
of the desired isomerization capability, and moldability and mechanical
strengths of the catalyst composition.

[0026]The present invention further provides a method for manufacturing a
hydroisomerization catalyst, the method comprising: a step a of
hydrothermally synthesizing a molecular sieve comprising a nanocrystal
having a pore structure of ten-membered rings or eight-membered rings and
having a ratio of the pore volume to the external surface area ([pore
volume]/[external surface area]) of 2.0×10-4 mL/m2 to
8.0×10-4 mL/m2 and comprising an organic template; a step
b of ion-exchanging the molecular sieve comprising an organic template in
a solution containing a cationic species to obtain an ion-exchanged
molecular sieve; a step c of making the ion-exchanged molecular sieve or
the calcined product thereof carry at least one metal selected from the
group consisting of metals of Groups 8 to 10 in Periodic Table of the
elements, molybdenum and tungsten to obtain a catalyst composition; and a
step d of calcining the catalyst composition.

[0027]Since the method for manufacturing the hydroisomerization catalyst
of the present invention comprises the above-mentioned steps, in the
hydroisomerization of a hydrocarbon oil containing normal paraffins, the
method can provide a hydroisomerization catalyst which is sufficiently
low in the cracking activity of normal paraffins and/or produced
isoparaffins when the normal paraffin conversion is sufficiently raised,
and has a high isomerization selectivity.

[0028]In the method for manufacturing the hydroisomerization catalyst of
the present invention, in the above-mentioned step c, a carrier is
preferably made to carry at least one metal selected from the group
consisting of metals of Groups 8 to 10 in Periodic Table of the elements,
molybdenum and tungsten to obtain the above-mentioned catalyst
composition, wherein the carrier is obtained by calcining a carrier
composition comprising 1 part by mass to 90 parts by mass of the
ion-exchanged molecular sieve and 99 parts by mass to 10 parts by mass of
at least one porous oxide selected from the group consisting of alumina,
silica, titania, boria, magnesia and zirconia.

[0029]The present invention also provides a method for dewaxing a
hydrocarbon oil, the method comprising bringing the hydrocarbon oil
containing normal paraffins having 10 or more carbon atoms into contact
with the above-mentioned hydroisomerization catalyst of the present
invention in the presence of hydrogen to convert a part of or the whole
of the normal paraffins into isoparaffins.

[0030]The above-mentioned hydrocarbon oil is preferably at least one
selected from the group consisting of slack wax, deoiled wax, paraffin
wax, microcrystalline wax, petrolatum, and wax from Fischer-Tropsch
synthesis.

[0031]The present invention further provides a method for manufacturing a
lube-oil base oil, the method comprising a step of bringing a hydrocarbon
oil containing normal paraffins having 10 or more carbon atoms into
contact with the above-mentioned hydroisomerization catalyst of the
present invention in the presence of hydrogen under the condition of a
conversion of the normal paraffins of substantially 100% by mass, wherein
the conversion is defined by the formula (I) described below:

[Expression 1]

Conversion of normal paraffins (%)=[1-(total mass % of normal paraffins
having Cn or more carbon atoms contained in a hydrocarbon oil after the
contact)/(total mass % of normal paraffins having Cn or more carbon atoms
contained in the hydrocarbon oil before the contact)]×100 (I)

wherein Cn denotes a minimum number of carbon atoms of normal paraffins
having 10 or more carbon atoms contained in the hydrocarbon oil before
the contact.

EFFECT OF THE INVENTION

[0032]The present invention can provide a hydroisomerization catalyst
which is sufficiently low in the cracking activity of normal paraffins
and/or produced isoparaffins when the normal paraffin conversion is
sufficiently raised in hydroisomerization of hydrocarbon oils containing
normal paraffins, and has a high isomerization selectivity, and can
provide a method for manufacturing the hydroisomerization catalyst.
Further, the present invention can provide, by using the
hydroisomerization catalyst, a method for dewaxing hydrocarbon oils, the
method enabling to obtain, stably and with a high yield, a hydrocarbon
oil suitable for lube-oil base oils and/or fuel base oils from
hydrocarbon oils containing normal paraffins, and also a method for
manufacturing a lube-oil base oil, the method enabling to obtain, with a
high yield, a high-performance lube-oil base oil from hydrocarbon oils
containing normal paraffins.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 is a plot diagram showing the normal decane conversion and
the C10-isomer yield obtained from an isomerization reaction using normal
decane vs. the reaction temperature; and

[0034]FIG. 2 is a plot diagram showing the normal decane conversion and
the C10-isomer yield obtained from an isomerization reaction using normal
decane vs. the reaction temperature.

BEST MODES FOR CARRYING OUT THE INVENTION

<Hydroisomerization Catalyst>

[0035]The hydroisomerization catalyst of the present invention is one
obtained by calcining a catalyst composition comprising an ion-exchanged
molecular sieve or a calcined product thereof, and at least one metal
selected from the group consisting of metals of Groups 8 to 10 in
Periodic Table of the elements, molybdenum and tungsten, carried on the
ion-exchanged molecular sieve or the calcined product thereof, wherein
the ion-exchanged molecular sieve is obtained by ion-exchanging a
molecular sieve, which comprises a nanocrystal having a pore structure of
ten-membered rings or eight-membered rings and having a ratio of the pore
volume to the external surface area ([pore volume]/[external surface
area]) of 2.0×10-4 mL/m2 to 8.0×10-4 mL/m2 and
comprises an organic template, in a solution containing a cationic
species.

[0036]In the hydroisomerization catalyst of the present invention, in the
case where the catalyst composition comprises a calcined product of an
ion-exchanged molecular sieve and the above-mentioned metal carried on
the calcined product, the calcined product of the ion-exchanged molecular
sieve may be contained in the catalyst composition as a carrier obtained
by calcining a carrier composition containing the ion-exchanged molecular
sieve, and the metal carried on the calcined product may be contained in
a form carried on the carrier in the catalyst composition.

[0037]A molecular sieve containing an organic template according to the
hydroisomerization catalyst of the present invention is not especially
limited as long as it is hydrothermally synthesized in the presence of
the organic template (hereinafter, referred to as synthesized molecular
sieve), but is preferably a zeolite. The molecular sieve containing an
organic template is more preferably a zeolite having a pore structure of
ten-membered rings or eight-membered rings, in view of simultaneously
satisfying both a high isomerization activity and a suppressed cracking
activity in the isomerization reaction of normal paraffins in a high
level. Such molecular sieves specifically include AEL, EUO, FER, HEU,
MEL, MFI, NES, TON, MTT, WEI and ZSM-48 type zeolites, which have a pore
structure of ten-membered rings, and ANA, CHA, ERI, GIS, KFI, LTA, NAT,
PAU, YUG and DDR type zeolites, which have a pore structure of
eight-membered rings. Here, each combination of these three alphabetical
characters indicates a skeletal structure code given to each structure of
classified molecular sieve type zeolites by The Structure Commission of
The International Zeolite Association. Further, zeolites having the same
topology are collectively designated as having the same code.

[0038]Among the above-mentioned zeolites, preferable are zeolites having
TON or MTT structures having one-dimensional pore structure of
ten-membered rings, and a crystalline aluminosilicate, ZSM-48 zeolite. As
a zeolite having TON structure, a crystalline aluminosilicate, ZSM-22, is
more preferable. As a zeolite having MTT structure, a crystalline
aluminosilicate, ZSM-23, is more preferable.

[0039]In the case of using a crystalline aluminosilicate, ZSM-22, ZSM-23
or ZSM-48 described above as a synthesized molecular sieve, the molar
ratio ([Si]/[Al], hereinafter, referred to as "Si/Al ratio") of silicon
and aluminum elements in these crystalline aluminosilicates is preferably
10 to 400, and more preferably 20 to 300. With the Si/Al ratio of less
than the lower limit, although the activity for conversion of normal
paraffins rises, the selectivity of isomerization to isoparaffins
decreases and there is a tendency of a sharp increase in the cracking
involved in a rise of the reaction temperature, which is not preferable.
By contrast, with the Si/Al ratio exceeding the upper limit, the catalyst
activity necessary for the conversion of normal paraffins can hardly be
obtained, which is not preferable.

[0040]An organic template used when a molecular sieve is hydrothermally
synthesized is selected depending on the structure of the molecular
sieve, but since the molecular sieve is synthesized usually under an
alkali condition, the organic template is preferably an amine derivative
in view that it can make an influence on properties of synthesis raw
materials small.

[0041]Further, the organic template is more preferably at least one
selected from the group consisting of alkylamines, alkyldiamines,
alkyltriamines, alkyltetramines, pyrrolidine, piperazine,
aminopiperazine, alkylpentamines, alkylhexamines, and derivatives
thereof.

[0042]The molecular sieve constituting the hydroisomerization catalyst of
the present invention has a form of a nanostructure. The nanostructure
used here corresponds to "nanorod" described in the document shown
before, "K. Hayasaka et al., Chemistry-A European Journal, 2007, 13,
10070-10077" (hereinafter, referred to as "Non-Patent Document 2"), and
indicates a microcrystal having a size of about 25 nm or less in length
in shorter axis direction (width: D).

[0043]A method for manufacturing a molecular sieve having a form of a
nanocrystal is not especially limited, but in the synthesis of the
molecular sieve by a usual hydrothermal synthesis, for example, making
the synthesis time shorter than usual and finishing the synthesis at a
stage before nanocrystals produced at the initial period of the synthesis
are aggregated to usual crystals can provide a molecular sieve having a
form of a nanocrystal. The details of this manufacturing method are
described in Non-Patent Document 2 shown above. As shown in FIG. 2 of
Non-Patent Document 2, nanocrystals of about 15 nm in length in shorter
axis direction are produced till a certain time passes after the
initiation of the hydrothermal synthesis of ZSM-22. If the hydrothermal
synthesis time is over a certain time, aggregation of nanocrystals
sharply occurs and aggregated crystals are produced and grow to a length
of the crystals in shorter axis direction over 30 nm and up to about 35
nm. Then, for the elapse of the hydrothermal synthesis time thereafter,
the length of the crystals in shorter axis direction does not largely
change.

[0044]The molecular sieve having a form of a nanocrystal constituting the
hydroisomerization catalyst of the present invention has a length of the
crystal in shorter axis direction preferably in the range of 5 to 30 nm,
and more preferably in the range of 5 to 25 nm. With the length in
shorter axis direction of less than 5 nm, since the formation of crystals
is insufficient and the crystals of the molecular sieve are liable to be
damaged when a catalyst is calcined and activated, the activity of the
catalyst is likely to decrease remarkably. With the length in shorter
axis direction of less than 5 nm, it is difficult to determine the length
of crystals in shorter axis direction by analytical means. On the other
hand, a catalyst constituted of aggregated crystals having a length of
the crystals in shorter axis direction exceeding 30 nm has such
tendencies that the cracking activity of normal paraffins and/or
isoparaffins in the region of a high normal paraffin conversion rises,
and it is difficult to obtain target isoparaffin fractions with a
sufficiently high yield.

[0045]The determination of the length of crystals in shorter axis
direction used here can be carried out by the X-ray diffraction analysis
(XRD), the nitrogen absorption test at -196° C. and the
transmission electron microscopic observation (TEM), described in
"Experimental Section" of Non-Patent Document 2. The above-mentioned
preferable range of the length of nanocrystals in shorter axis direction
was obtained by XRD.

[0046]The molecular sieve having a form of a nanocrystal constituting the
hydroisomerization catalyst of the present invention has a smaller pore
volume of crystals and a larger external surface area thereof determined
by the nitrogen absorption test at -196° described in Non-Patent
Document 2 than those of aggregated crystals, and has a ratio of the pore
volume to the external surface area (a ratio of pore volume/external
surface area) in the range of 2.0×10-4 mL/m2 to
8.0×10-4 mL/m2. The ratio is more preferably
2.5×10-4 mL/m2 to 7.0×10-4 mL/m2. With
the ratio of pore volume/external surface area of the molecular sieve of
less than the above-mentioned lower limit, since the formation of
crystals is insufficient and the crystals of the molecular sieve are
liable to be damaged when the catalyst is calcined and activated, the
activity of the hydroisomerization catalyst constituted of such a
molecular sieve is likely to decrease the activity remarkably. By
contrast, with that exceeding the upper limit, in the hydroisomerization
catalyst constituted of such a molecular sieve, the isomerization
selectivity in a high normal paraffin conversion region is likely to
decrease. Here, as the pore volume and the external surface area of a
molecular sieve, values are employed which are determined by carrying out
the nitrogen absorption test at -196° C. for the molecular sieve
in the state that an organic template has been removed by calcination and
thereafter, the ion-exchange treatment has been carried out. The removal
of an organic template by calcination can be carried out, for example, by
heating a molecular sieve after hydrothermal synthesis at a rate of
5° C./min to 400° C. in a quartz tube furnace in a nitrogen
gas flow, thereafter holding the molecular sieve in the conditions for 6
hours, then changing over the nitrogen gas flow to an oxygen gas flow,
raising the temperature at 5° C./min up to 550° C., and
thereafter holding the temperature at 550° C. for about 12 hours.
The ion-exchange treatment thereafter can be carried out, for example, by
adding 0.5N ammonium chloride aqueous solution to the calcined molecular
sieve and refluxing by heating for about 12 hours. After the finish of
the ion-exchange, a solid content is sampled by filtering, washed with
ion-exchange water, and dried in a drier at 60° C. for about 12
hours to obtain an ion-exchanged molecular sieve from which the organic
template has been removed, which ion-exchanged molecular sieve is used as
a test specimen for the pore volume and the external surface area.

[0047]Meanwhile, conventional molecular sieves constituting
hydroisomerization catalysts are, after hydrothermally synthesized,
calcined usually in an atmosphere containing molecular oxygen at a
temperature of 550° C. or higher for removing an organic template
present therein. The temperature is selected for sufficiently burning and
removing the organic template. Then, after the calcination, the
ion-exchange, carrying of a metal component and activation by calcination
are carried out to manufacture conventional catalysts. By contrast, the
hydroisomerization catalyst of the present invention is manufactured by
using an ion-exchanged molecular sieve obtained by subjecting a molecular
sieve composed of the above-mentioned specified microcrystal and in the
state of containing an organic template to an ion-exchange treatment in a
solution containing a cationic species.

[0048]In the present invention, a molecular sieve containing an organic
template can suffice as long as the organic template has not been
substantially all removed by calcination. That is, as long as the
calcination of a synthesized molecular sieve is not at all carried out,
or it is not calcined under the condition (especially a high temperature)
where the organic template is substantially all burned and removed even
in the case where the calcination is carried out, before the organic
template is removed by the ion-exchange, the molecular sieve can suffice.
In the case where a synthesized molecular sieve is calcined in an
atmosphere containing molecular oxygen, the calcination temperature is
preferably about 500° C. or less, more preferably 450° C.
or less, and still more preferably 400° C. or less, so that the
organic template is not substantially all burned and removed. Most
preferably in the present invention, before the organic template is
removed by the ion-exchange, the calcination of the synthesized molecular
sieve is not at all carried out.

[0049]The case where a molecular sieve containing an organic template is,
before subjected to an ion-exchange treatment, calcined under the
condition where the organic template is substantially all burned and
removed, has a tendency of not providing characteristics the
hydroisomerization catalyst of the present invention could have, that is,
characteristics by which the cracking of normal paraffins and/or
isoparaffins is sufficiently suppressed in a high normal paraffin
conversion region in the hydroisomerization reaction of the normal
paraffins.

[0050]The ion-exchange for obtaining an ion-exchanged molecular sieve
constituting the hydroisomerization catalyst of the present invention is
carried out by ion-exchanging a molecular sieve containing an organic
template preferably in a solution containing water as a main solvent and
a cationic species. "Containing water as a main solvent" used here means
that the content of the water contained in the solution is 50% by mass or
more based on the total amount of solvents in the solution. In the
present invention, the water content is preferably 70% by mass or more,
and more preferably 100% by mass or more.

[0051]In the case where the solution contains an organic solvent, the
content thereof is preferably 50% by mass or less, and more preferably
30% by mass or less, based on the total amount of solvents in the
solution. With the content of the organic solvent exceeding 50% by mass,
for example, the case of using a compound to supply a cationic species
for ion-exchange is liable to raise problems such as a decrease in the
solubility of the compound to the solvent. Therefore, most preferably,
the solution contains no organic solvent.

[0052]In a molecular sieve in the hydrothermally synthesized state, there
is present generally an alkali metal cation or an alkalin earth metal
cation as a counter cation. In the above-mentioned ion-exchange, such a
counter cation is also ion-exchanged, and simultaneously, an organic
template is also removed reasonably.

[0053]A cationic species contained in the solution is not especially
limited, and various types of cationic species can be used, but they are
preferably proton or ammonium ion in view of forming Bronsted acid sites
useful in the catalyst according to the present invention. In the case of
using proton as a cationic species, a mineral acid such as hydrochloric
acid, sulfuric acid or nitric acid is usually utilized. An ammonium type
molecular sieve obtained by ion-exchanging a synthesized molecular sieve
in the presence of ammonium ions releases ammonia in a later calcination
of a catalyst composition, and counter cations turn to protons to become
Bronsted acid sites. Compounds to supply ammonium ions in a solution
include various inorganic and organic salts of ammonium such as ammonium
chloride, ammonium sulfate, ammonium nitrate, ammonium phosphate and
ammonium acetate. The most preferable cationic species in the present
invention is ammonium ion. The content of a cationic species contained in
a solution is preferably set at 10 to 1,000 equivalent weight with
respect to the total amount of an organic template and a counter cation
contained in a molecular sieve to be used.

[0054]The above-mentioned ion-exchange is carried out preferably by a
method in which a powdery synthesized molecular sieve, a molded product
of a synthesized molecular sieve or a molded product of a mixture of a
synthesized molecular sieve and a binder is immersed in a solution
containing a cationic species, preferably in an aqueous solution, and
stirred or fluidized.

[0055]The stirring or fluidization is preferably carried out under heating
to raise the efficiency of the ion-exchange. In the present invention, a
method in which an aqueous solution containing a cationic species is
heated, and the ion-exchange is carried out under boiling and refluxing
is especially preferable.

[0056]The time of the ion-exchange depends on other conditions, but is
preferably about 1 to 24 hours. The amount of the solution brought into
contact with a synthesized molecular sieve is preferably 0.01 L to 10 L
based on 1 g of the synthesized molecular sieve in view of the
ion-exchange efficiency and the economic efficiency. Further, in view of
enhancing the ion-exchange efficiency, during the ion-exchange of the
synthesized molecular sieve in the solution, the solution is preferably
replaced by a new one once or more, and more preferably once or twice. In
the case where the solution is replaced once, for example, a synthesized
molecular sieve is immersed in an aqueous solution containing a cationic
species; the solution is refluxed under heating for 1 to 6 hours; then,
the solution is replaced by a new one; and thereafter, the solution is
further refluxed under heating for 6 to 12 hours, enabling to enhance the
ion-exchange efficiency.

[0057]Preferably, the ion-exchanged molecular sieve is preparatively
isolated by filtering or the like, thereafter, washed with deionized
water or the like, and dried at about 60 to 130° C. for about 10
to 48 hours.

[0058]On the ion-exchanged molecular sieve, at least one metal selected
from the group consisting of metals of Groups 8 to 10 of Periodic Table
of the elements, molybdenum and tungsten is carried. Preferable metals of
Groups 8 to 10 of Periodic Table of the elements include iron, ruthenium,
osmium, cobalt, rhodium, iridium, nickel, palladium and platinum.
Further, among these, platinum and/or palladium is preferable and
platinum is more preferable in view of activity, selectivity and
durability of activity. Metals of Groups 8 to 10 of Periodic Table of the
elements, molybdenum and tungsten may be used singly or in combination of
two or more.

[0059]In the case where the hydroisomerization catalyst of the present
invention is used for the hydroisomerization of a hydrocarbon oil
containing much of a sulfur-containing compound and/or a
nitrogen-containing compound, a combination of metals, such as
nickel-cobalt, nickel-molybdenum, cobalt-molybdenum,
nickel-molybdenum-cobalt or nickel-tungsten-cobalt, carried on an
ion-exchanged molecular sieve is preferable in view of durability of the
catalyst activity.

[0060]Methods in which the above-mentioned metal is carried on an
ion-exchanged molecular sieve include well-known methods such as the
impregnation methods (equilibrium adsorption method, pore filling method,
incipient wetting method) and the ion-exchange method. The compounds
containing the above-mentioned metal element component used at this time
include hydrochloric salts, sulfuric salts, nitric salts and complex
compounds of the metals. Compounds containing platinum include
chloroplatinic acid, tetramminedinitroplatinum, dinitroaminoplatinum and
tetramminedichloroplatinum.

[0061]The carrying amount of the above-mentioned metal on an ion-exchanged
molecular sieve is preferably 0.001 to 20% by mass with respect to the
mass of the ion-exchanged molecular sieve. With the carrying amount of
less than the lower limit, it is difficult to impart a predetermined
hydrogenation/dehydrogenation function; by contrast, with that exceeding
the upper limit, turning into light oils due to cracking of hydrocarbons
on the metal is liable to progress; the yield of target fractions is
likely to decrease; and further, the rising of catalyst costs is likely
to be invited.

[0062]The condition of calcining a catalyst composition containing the
ion-exchanged molecular sieve and the metal carried on the ion-exchanged
molecular sieve is in an atmosphere containing molecular oxygen,
preferably at 250° C. to 600° C., and more preferably at
300 to 500° C. The atmosphere containing molecular oxygen
includes, for example, oxygen gas, oxygen gas diluted with an inert gas
such as nitrogen gas, and air. The calcination time is usually about 0.5
to 20 hours. Through such a calcination treatment, a compound containing
the metal element carried on the ion-exchanged molecular sieve is
converted to a metal single substance, its oxide or the like species,
whereby the catalyst is imparted the isomerization activity of normal
paraffins. If the calcination temperature is out of the above range, the
activity and the selectivity of the catalyst are likely to be
insufficient.

[0063]According to the calcination treatment described above, if an
organic template remains on the ion-exchanged molecular sieve, it is also
possible to burn and completely remove the remaining organic template.
Further, in the present invention, the calcination at a relatively low
temperature can sufficiently remove the organic template. This is
considered because since the above-mentioned metal having a catalytic
capability for oxidation reaction is carried on the ion-exchanged
molecular sieve according to the present invention, the action thereof
can progress the oxidation reaction (combustion) of the organic template
at a lower temperature.

[0064]In the case where the ion-exchanged molecular sieve is an ammonium
type molecular sieve, the counter cations of ammonium release ammonia to
make protons and to form Bronsted acid sites in the above-mentioned
calcination process.

[0065]The hydroisomerization catalyst according to the present invention
is, following the above-mentioned calcination treatment, preferably a
hydroisomerization catalyst subjected to a reduction treatment preferably
in an atmosphere containing molecular hydrogen, at 250 to 500° C.,
more preferably 300 to 400° C., for about 0.5 to 5 hours. Through
such processes, a high activity for dewaxing hydrocarbon oils can be
securely imparted to the catalyst.

[0066]In the hydroisomerization catalyst according to the present
invention, the catalyst composition is preferably molded in a
predetermined shape. The shapes include, for example, a cylindrical
shape, pelletized shape, spherical shape, and deformed cylindrical shape
having three-leaved or four-leaved cross-section. Molding the catalyst
composition in such a shape enhances mechanical strengths of the catalyst
obtained by calcination, improves the handleability of the catalyst, and
allows for reduction of the pressure loss of a reaction fluid in the
reaction. For molding of the catalyst composition, a well-known method is
utilized.

[0067]The content of an ion-exchanged molecular sieve or a calcined
product thereof in a catalyst composition is preferably 1 to 90% by mass,
and more preferably 10 to 80% by mass, based on the total amount of the
catalyst composition.

[0068]Further, the catalyst composition preferably comprises at least one
porous oxide selected from the group consisting of alumina, silica,
titania, boria, magnesia and zirconia in view of improving moldability of
the catalyst and mechanical strengths of the molded catalyst. In this
case, the content proportions of an ion-exchanged molecular sieve and the
porous oxide in the catalyst composition are preferably 1 to 90% by mass
and 99 to 10% by mass, and more preferably 10 to 80% by mass and 90 to
20% by mass, respectively. In the hydroisomerization catalyst according
to the present invention, in the case where the catalyst composition
comprises a calcined product of an ion-exchanged molecular sieve and the
above-mentioned metal carried on the calcined product, the calcined
product of an ion-exchanged molecular sieve may be contained in a
catalyst composition as a carrier obtained by calcining a carrier
composition comprising the ion-exchanged molecular sieve, and the metal
carried on the calcined product may be contained in a form carried on the
carrier in the catalyst composition.

[0069]In the case where the above-mentioned porous oxide is contained in a
catalyst composition, a carrier comprising a carrier composition
containing an ion-exchanged molecular sieve and a porous oxide may be
molded before the above-mentioned metal is carried on the ion-exchanged
molecular sieve, or the ion-exchanged molecular sieve carrying the metal,
and the porous oxide may be mixed and molded. In the present invention,
the former is preferable. That is, preferably, after a synthesized
molecular sieve containing an organic template is ion-exchanged in a
solution containing a cationic species, a carrier composition obtained by
mixing this ion-exchanged molecular sieve, the above-mentioned porous
oxide, and optionally other binder components is molded. The obtained
molded product is preferably calcined in an atmosphere containing
molecular oxygen to bring out solid acids of the porous oxide. Further,
the catalyst composition preferably comprises: a carrier obtained by
molding and calcining a carrier composition comprising 1 part by mass to
90 parts by mass of the ion-exchanged molecular sieve and 99 parts by
mass to 10 parts by mass of at least one porous oxide selected from the
group consisting of alumina, silica, titania, boria, magnesia and
zirconia; and the above-mentioned metal carried on the carrier.

[0070]In the hydroisomerization catalyst according to the present
invention, a metal other than metals of Groups 8 to 10 of Periodic Table
of the elements, molybdenum and tungsten may further be carried on the
ion-exchanged molecular sieve or a calcined product thereof in the range
of not damaging the advantages of the present invention. Further, in the
case where the catalyst composition comprises a porous oxide, a metal
other than metals of Groups 8 to 10 of Periodic Table of the elements,
molybdenum and tungsten may further be carried on the ion-exchanged
molecular sieve or a calcined product thereof and/or the porous oxide.

<Manufacturing Method of the Hydroisomerization Catalyst>

[0071]Then, a method for manufacturing the hydroisomerization catalyst of
the present invention will be described.

[0072]A method of manufacturing a hydroisomerization catalyst of the
present invention, comprising: a step a of hydrothermally synthesizing a
molecular sieve comprising a nanocrystal having a pore structure of
ten-membered rings or eight-membered rings and having a ratio of the pore
volume to the external surface area ([pore volume]/[external surface
area]) of 2.0×10-4 mL/m2 to 8.0×10-4
mL/m2 and comprising an organic template; a step b of ion-exchanging
the molecular sieve comprising an organic template in a solution
containing a cationic species to obtain an ion-exchanged molecular sieve;
a step c of making the ion-exchanged molecular sieve or the calcined
product thereof carry at least one metal selected from the group
consisting of metals of Groups 8 to 10 in Periodic Table of the elements,
molybdenum and tungsten to obtain a catalyst composition; and a step d of
calcining the catalyst composition.

[0073]A method for synthesizing the molecular sieve containing an organic
template in the step a described above include the method described in
the description of the hydroisomerization catalyst of the present
invention. The molecular sieve is preferably synthesized by suitably
controlling the hydrothermal synthesis time, temperature and the like so
that the length in the shorter axis direction of nanocrystals is in the
range of 5 to 25 nm.

[0074]A method for ion-exchanging the molecular sieve containing an
organic template in the step b described above includes the method
described in the description of the hydroisomerization catalyst of the
present invention.

[0075]A method for making the above-mentioned metal carried on an
ion-exchanged molecular sieve or a calcined product thereof in the step c
described above includes the method described in the description of the
hydroisomerization catalyst of the present invention.

[0076]In the manufacturing method of the hydroisomerization catalyst of
the present invention, the step c described above preferably comprises
making a carrier, which is obtained by calcining a carrier composition
comprising 1 part by mass to 90 parts by mass of the ion-exchanged
molecular sieve or the calcined product thereof and 99 parts by mass to
10 parts by mass of at least one porous oxide selected from the group
consisting of alumina, silica, titania, boria, magnesia and zirconia,
carry at least one metal selected from the group consisting of metals of
Groups 8 to 10 in Periodic Table of the elements, molybdenum and tungsten
to obtain the catalyst composition.

[0077]A method for calcining the catalyst composition in the step d
described above includes the method described in the description of the
hydroisomerization catalyst of the present invention.

[0078]Further, in the manufacturing method of the hydroisomerization
catalyst of the present invention, after the calcination of the catalyst
composition in the step d described above, the catalyst is preferably
subjected to a reduction treatment preferably in an atmosphere containing
molecular hydrogen, at 250 to 500° C., more preferably 300 to
400° C., for about 0.5 to 5 hours. Through such steps, a high
activity for dewaxing hydrocarbon oils can be imparted more securely.

[0079]The greatest feature of the hydroisomerization catalyst of the
present invention lies in that the hydroisomerization catalyst is
constituted of an ion-exchanged molecular sieve obtained by
ion-exchanging a specified molecular sieve having a morphology of
nanocrystals in the state containing an organic template. A
hydroisomerization catalyst constituted of a molecular sieve having a
morphology of nanocrystals, as described in the final paragraph on the
left column in page 10074, and "Table 2" in Non-Patent Document 2 shown
before, more decreases in the isomerization (and cracking) activity of
normal paraffins than a similar catalyst constituted of a molecular sieve
having a form of usual crystals.

[0080]By contrast, although the hydroisomerization catalyst of the present
invention more decreases in the activity than a similar catalyst
constituted of a conventional ion-exchanged molecular sieve having usual
crystals and obtained by ion-exchange after removal of an organic
template by calcination, it largely increases in the isomerization
selectivity, and exhibits a remarkably high isomerization selectivity
especially in a high normal paraffin conversion range. Therefore, the
hydroisomerization catalyst of the present invention can improve the
yield of an isomerized product in a high normal paraffin conversion
range.

[0081]The present inventors have found that although a hydroisomerization
catalyst constituted of an ion-exchanged molecular sieve obtained by
ion-exchanging a specified molecular sieve having a usual crystal
morphology in the state containing an organic template slightly more
decreases in the activity than a similar catalyst constituted of a
conventional ion-exchanged molecular sieve, it improves in the
isomerization selectivity (isomerization activity/(isomerization
activity+cracking activity). By contrast, the hydroisomerization catalyst
of the present invention allows for further improvement in the
isomerization selectivity, and can further improve the yield of an
isomerized product in a high normal paraffin conversion region.

[0082]In the hydroisomerization catalyst of the present invention, the
mechanism to develop the feature as described above cannot be definitely
said, but the present inventors surmise as follows.

[0083]Acid sites in a molecular sieve are considered to include those
contributing to the isomerization of normal paraffins and those
contributing to the cracking of normal paraffins. A theory is proposed in
which the former sites are acid sites existing in the vicinity of pore
entrances of the molecular sieve and the latter sites are acid sites
existing in the interior of pores. The latter is considered to decompose
also isoparaffins having a few branches produced by the isomerization. A
molecular sieve having a morphology of nanocrystals is considered to have
fewer of both the acid sites than a molecular sieve having a morphology
of aggregated crystals, and to be lower in the isomerization activity and
the cracking activity as well.

[0084]By contrast, although a hydroisomerization catalyst constituted of
an ion-exchanged molecular sieve obtained by ion-exchanging a molecular
sieve containing an organic template more decreases in the isomerization
activity than a similar catalyst constituted of a conventional
ion-exchanged molecular sieve obtained by ion-exchange after removal of
an organic template by calcination, the cracking activity decreases more
than that decrease, resulting in having a high isomerization selectivity.
This is presumably because the former catalyst can more hardly produce
acid sites in pores than the latter catalyst for some reason.

[0085]In the hydroisomerization catalyst of the present invention, since a
molecular sieve having a morphology of nanocrystals is ion-exchanged in
the state of containing an organic template, the production amount of
acid sites in the interior of pores is presumably small, and the present
inventors presume that the isomerization selectivity is thereby improved
to such a degree that the isomer yield is kept high even in a high normal
paraffin conversion region.

[0086]Application of the hydroisomerization catalyst of the present
invention to the hydroisomerization of hydrocarbon oils containing
high-boiling point normal paraffins as a main component enables to
manufacture, with an economical yield, high-boiling point isoparaffin
fractions containing substantially no normal paraffin, which is required
especially for high-performance lube-oil base oils.

<Dewaxing Method of Hydrocarbon Oils>

[0087]Then, a method for dewaxing hydrocarbon oils of the present
invention will be described. The method for dewaxing hydrocarbon oils of
the present invention comprises a step of bringing the hydrocarbon oils
containing normal paraffins having 10 or more carbon atoms into contact
with the hydroisomerization catalyst of the present invention in the
presence of hydrogen to convert a part of or the whole of the normal
paraffins into isoparaffins.

[0088]Hydrocarbon oils used in the dewaxing method of the hydrocarbon oils
of the present invention are not especially limited as long as the
hydrocarbon oils contain normal paraffins having 10 or more, preferably
15 or more, carbon atoms. The hydrocarbon oils specifically include
various ones from relatively light distillate fractions such as kerosene
and jet fuel to all crude oils, atmospheric distillation residual oils,
vacuum column residual oils, reduced pressure residual oils, cycle
stocks, synthetic crude oils (for example, shale oil and tar oil), gas
oils, vacuum gas oils, foot's oils, fuel fractions and wax fractions
derived from FT synthesized oils, and to high-boiling point raw oils such
as other heavy oils. These hydrocarbon oils may contain wax components
composed of naphthenic hydrocarbons having a long straight-chain alkyl
group as side chains, or aromatic hydrocarbons, other than normal
paraffins.

[0089]Especially preferable hydrocarbon oils to be dewaxed by the dewaxing
method of hydrocarbon oils of the present invention are those constituted
of hydrocarbons having a boiling point of 180° C. or more and
having 10 or more carbon atoms. Since hydrocarbon oils lighter than these
usually contain substantially no wax components affecting the cold flow
property, the necessity of dewaxing is low, hardly providing the
advantages of the present invention.

[0090]On the other hand, the application of the dewaxing method according
to the present invention is especially effective to fractions of
distillate raw oils containing wax components, i.e. intermediate oil
fraction raw oils including gas oils, kerosenes and jet fuels, lube-oil
raw oils, oils for air heating, and other distillate fractions, whose
pour points and viscosities must be kept in a predetermined range. Such
hydrocarbon oils include, for example, gas oils subjected to a
hydrotreating or a hydrocracking, heavy gas oils, vacuum gas oils,
lube-oil raffinates, lube-oil raw materials, bright stocks, slack waxes,
foot's oils, deoiled waxes, paraffin waxes, microcrystalline waxes,
petrolatums, synthetic oils, FT synthetic oils, high-pour point
polyolefins, and straight-chain α-olefin waxes. These can be used
singly or in combination of two or more.

[0091]The temperature of the hydroisomerization reaction in the dewaxing
method of hydrocarbon oils of the present invention is generally 200 to
450° C., and preferably 220 to 400° C. With the reaction
temperature below 200° C., the isomerization of normal paraffins
contained in hydrocarbon oils as a raw material hardly progresses and the
reduction and removal of wax components are likely to be insufficient. By
contrast, with the reaction temperature exceeding 450° C., the
cracking of the hydrocarbon oils becomes remarkable and the yield of
target base oils is likely to decrease.

[0092]The pressure of the hydroisomerization reaction in dewaxing of
hydrocarbon oils of the present invention is generally 0.1 to 20 MPa, and
preferably 0.5 to 15 MPa. With the pressure below 0.1 MPa, the
degradation of the catalyst due to coke production is likely to become
fast. By contrast, with the pressure exceeding 20 MPa, an economical
process is likely to be hardly achieved because of high facility building
costs.

[0093]The liquid space velocity of hydrocarbon oils with respect to the
catalyst in the hydroisomerization reaction in the dewaxing method of
hydrocarbon oils of the present invention is generally 0.01 to 100
hr-1, and preferably 0.1 to 50 hr-1. With the liquid space
velocity of less than 0.01 hr-1, the cracking of the hydrocarbon
oils is liable to excessively progress and the production efficiency of
target base oils is likely to decrease. By contrast, with the liquid
space velocity exceeding 100 hr-1, the isomerization of normal
paraffins contained in the hydrocarbon oils hardly progress and the
reduction and removal of wax components are likely to be insufficient.

[0094]The supply ratio of hydrogen and a hydrocarbon oil in the
hydroisomerization reaction in the dewaxing method of hydrocarbon oils of
the present invention is generally 100 to 1,000 Nm3/m3, and
preferably 200 to 800 Nm3/m3. With the supply ratio of less
than 100 Nm3/m3, for example, in the case where a raw oil
contains a sulfur and nitrogen compounds, since hydrogen sulfide and
ammonia gases generated by desulfurization and denitrification reactions
occurring simultaneously with the isomerization reaction are adsorbed on
and poison an active metal on the catalyst, a predetermined catalyst
performance is likely to be hardly provided. By contrast, with the supply
ratio exceeding 1,000 Nm3/m3, an economical process is likely
to be hardly achieved because a large-capacity hydrogen supply facility
is needed.

[0095]The conversion of normal paraffins in the hydroisomerization
reaction in the dewaxing method of hydrocarbon oils of the present
invention is suitably controlled depending on applications of target base
oils.

<Manufacturing Method of Lube-Oil Base Oils>

[0096]Then, a method for manufacturing lube-oil base oils of the present
invention will be described. The method for manufacturing lube-oil base
oils of the present invention has such a feature that a hydrocarbon oil
containing normal paraffins having 10 or more carbon atoms is brought
into contact with the hydroisomerization catalyst of the present
invention in the presence of hydrogen under such a condition that the
conversion of the normal paraffins defined by the formula (I) described
below is substantially 100% by mass. Here, "conversion is substantially
100% by mass" means that the content of normal paraffins contained in the
hydrocarbon oil after the contact is 0.1% by mass or less.

[Expression 2]

Conversion of normal paraffins (%)=[1-(total mass % of normal paraffins
having Cn or more carbon atoms contained in a hydrocarbon oil after the
contact)/(total mass % of normal paraffins having Cn or more carbon atoms
contained in the hydrocarbon oil before the contact)]×b 100 (I)

wherein Cn denotes a minimum number of carbon atoms of normal paraffins
having 10 or more carbon atoms contained in the hydrocarbon oil before
the contact.

[0097]Hydrocarbon oils used in the manufacturing method of lube-oil base
oils of the present invention are not especially limited as long as they
contain normal paraffins having 10 or more carbon atoms, but preferably
contain a hydrocarbon oil having a higher initial boiling point than that
of desired lube-oil base oils. As such raw oils suitable are petroleum
fractions and synthetic oils and waxes whose boiling points exceed
360° C. in terms of ambient pressure. They specifically include
heavy gas oils, vacuum gas oils, lube-oil raffinates, bright stocks,
slack waxes, foot's oils, deoiled waxes, paraffin waxes, microcrystalline
waxes, petrolatums, synthetic oils, FT synthetic oils, high-pour point
polyolefins, and straight-chain α-olefin waxes. These can be used
singly or in combination of two or more. Further, these oils are
preferably those having been subjected to a hydrotreating or a mild
hydrocracking. These treatments can reduce or remove substances causing
activity reduction of the hydroisomerization catalyst, such as
sulfur-containing compounds and nitrogen-containing compounds, and
substances decreasing the viscosity indexes of lube-oil base oils such as
aromatic hydrocarbons and naphthenic hydrocarbons.

[0098]By using a relatively heavy hydrocarbon oil described above as a raw
oil and bringing it into contact with the hydroisomerization catalyst
according to the present invention in the presence of hydrogen, the
isomerization of normal paraffins contained in the hydrocarbon oil, that
is, the dewaxing reaction of the hydrocarbon oil, can be progressed while
turning into light oils is sufficiently suppressed. Thereby, a lube-oil
base oil in which the proportion of fractions thereof whose boiling
points exceed 360° C. in terms of ambient pressure is 90% by
volume or more can be provided with a high yield. The manufacturing
method of lube-oil base oils according to the present invention can
provide a lube-oil base oil containing much of isomers having a
branched-chain structure. Although, particularly, high-quality lube-oil
base oils are required to have a content of normal paraffins of 0.1% by
mass or less, the manufacturing method of lube-oil base oils according to
the present invention can provide a lube-oil base oil satisfying the
requirement with a high yield.

[0099]In the hydroisomerization of a hydrocarbon oil containing normal
paraffins, usually since, for example, raising the reaction temperature
can increase the conversion of the normal paraffins, and decrease the
normal paraffin content in the reaction product, the cold flow property
of the hydrocarbon oil can be improved. However, since raising the
reaction temperature promotes the cracking of the hydrocarbon oil as the
raw material and the isomerized product, light fractions increase along
with the rising conversion of the normal paraffins. Since the increase in
light fractions causes a decrease in the viscosity index of the
hydrocarbon oil, the light fractions must be separated and removed by
distillation or the like in order to fall the performance as a lube-oil
base oil in a predetermined range. Particularly in the case where
high-performance lube-oil base oils such as Group III+ according to the
classification of lube-oil grades by American Petroleum Institute are
manufactured by catalytic dewaxing of hydrocarbon oils, the normal
paraffin conversion in the hydrocarbon oils as a raw material must be
substantially 100%. By manufacturing methods of lube-oil base oils using
a conventional catalyst for catalytic dewaxing, under the condition that
the normal paraffin conversion is substantially 100%, the yield of the
above-mentioned high-performance lube-oil base oil is extremely low. By
contrast, by the manufacturing method of lube-oil base oils of the
present invention, even if the hydrotreating process is carried out under
the condition that the normal paraffin conversion is substantially 100%,
the yield of the above-mentioned high-performance lube-oil base oil can
be held at a high level.

[0100]Facilities to conduct the dewaxing method of hydrocarbon oils and
the manufacturing method of lube-oil base oils of the present invention
are not especially limited, and well-known ones can be used. A reaction
facility may be any of a continuous circulation system, a batch system
and a semibatch system, but is preferably of a continuous circulation
system in view of productivity and efficiency. A catalyst layer may be
any of a fixed bed, a fluidized bed and an agitated bed, but is
preferably of a fixed bed in view of the facility cost and the like. A
reaction phase is preferably a vapor-liquid mixed phase.

[0101]In the dewaxing method of hydrocarbon oils and the manufacturing
method of lube-oil base oils of the present invention, as a prestage of
the dewaxing step by the above-mentioned hydroisomerization reaction,
hydrocarbon oils as a supplied raw material may be subjected to a
hydrotreating or a hydrocracking treatment. As the facility, catalyst and
reaction condition, well-known ones can be used. By conducting these
pretreatments, the activity of the hydroisomerization catalyst of the
present invention can be maintained over a long period, and can reduce
environmental load substances in products such as sulfur- and
nitrogen-containing compounds.

[0102]Further, in the manufacturing method of lube-oil base oils of the
present invention, a reaction product obtained by the above-mentioned
dewaxing process is further subjected to a treatment, for example,
hydrofinishing. The hydrofinishing can generally be carried out by
bringing a product to be hydrofinished into contact with a carried metal
hydrogenation catalyst (for example, platinum carried on alumina) in the
presence of hydrogen. Conducting such a hydrofinishing can improve the
hue, oxidation stability and the like of a reaction product obtained by
the dewaxing process, thus improving the quality of a product. The
hydrofinishing may be carried out in a reaction facility separated from
the dewaxing process, but may be carried out following the dewaxing
process by providing a catalyst layer for hydrofinishing downstream of a
catalyst layer of the hydroisomerization catalyst according to the
present invention provided in a reactor to conduct the dewaxing process.

[0103]Usually, "isomerization" refers to a reaction in which the number of
carbons (molecular weight) does not change and only the molecular
structure changes, and "cracking" refers to a reaction involving a
decrease in the number of carbons (molecular weight). In a catalytic
dewaxing reaction utilizing the isomerization reaction, even if the
cracking of hydrocarbons as a feed stock and an isomerized product is
generated to some extent, the cracking is allowed as long as it falls
within a predetermined range where the number of carbons (molecular
weight) of the cracking products is allowed to constitute a target base
oil, and the cracking products are allowed to be constituent of the base
oil.

Examples

[0104]Hereinafter, the present invention will be described further in
detail by way of Examples, but the scope of the present invention is not
limited to these Examples.

Example 1 and Comparative Examples 1 to 7

[0105]1. Evaluation of Catalysts by Model Reactions

[0106]1-1. Manufacture of Catalysts

[0107]1-1-1. Manufacture of ZSM-22 Type Zeolite

[0108]ZSM-22 type zeolite composed of a crystalline aluminosilicate having
a Si/Al ratio of 30 was manufactured by the following procedure according
to the method described in page 1007, "Experimental Section" of
Non-Patent Document 2 shown before.

[0114]Then, Solution A was added to Solution B and stirred till the
aluminum component was completely dissolved. Solution C was added to the
mixed solution, and thereafter, the mixture of Solutions A, B and C was
poured in Solution D under vigorous stirring at room temperature.
Further, thereto, 0.25 g of a powder of ZSM-22 which had been synthesized
separately and had not been subjected to any special treatment after the
synthesis was added as a "seed crystal" to promote the crystallization to
obtain a gelatinous material.

[0115]Further three gelatinous materials having the same composition as
the above were prepared as in the above-mentioned operation. The four
gelatinous materials were transferred in four stainless steel autoclave
reactors of 120 mL in internal volume, and subjected to a hydrothermal
synthesis reaction, respectively, for 27 hours, 29 hours, 31 hours and 33
hours while the autoclave reactors were rotated at a rotation frequency
of about 60 rpm on a tumbling apparatus in an oven at 150° C.
After the finish of the respective reactions, the reactors were cooled;
respective solid contents produced in the respective reactors were
sampled by filtration, washed with ion-exchange water, and dried
overnight in a drier at 60° C. to obtain four kinds of ZSM-22
having a Si/Al ratio of 30.

[0116]1-1-2. Ion-Exchange of ZSM-22 Containing an Organic Template

[0117]The four kinds of ZSM-22 obtained as described above were each
partly sampled and each was subjected to an ion-exchange treatment in an
aqueous solution containing ammonium ions by the following operation.

[0118]ZSM-22 obtained as described above were each charged in a flask, and
100 mL of a 0.5N ammonium chloride aqueous solution was added thereto
with respect to 1 g of each ZSM-22, and refluxed under heating for 6
hours. After the solution was cooled to room temperature, a supernatant
solution was removed, and a crystalline aluminosilicate was washed with
ion-exchange water. Then, the same amount of the 0.5N ammonium chloride
aqueous solution was again added thereto, and refluxed under heating for
12 hours.

[0119]Thereafter, respective solid contents were sampled by filtration,
washed with ion-exchange water, and dried overnight in a drier at
60° C. to obtain respective ion-exchanged NH4 type ZSM-22.
These ZSM-22 are those ion-exchanged in the state containing an organic
template. Hereinafter, the respective ion-exchanged NH4 type ZSM-22
obtained as described above are denoted as "ZSM-22[27]IE",
"ZSM-22[29]IE", "ZSM-22[31]IE", and "ZSM-22[33]IE", respectively. Here,
IE expresses having been ion-exchanged in the state containing an organic
template without calcination, and a numeral in [ ] expresses a
hydrothermal synthesis time.

[0120]1-1-3. Ion-Exchange After Removal of the Organic Template by
Calcination

[0121]Four kinds of ZSM-22 obtained as described above were each filled in
a quartz tube furnace, and heated at a rate of 5° C./min to
400° C. in a nitrogen gas flow, and held in the conditions for 6
hours. Thereafter, the circulating gas was changed over to oxygen gas;
and the ZSM-22 was further heated at 5° C./min to 550° C.,
and held overnight in the conditions at 550° C. Here, the
calcination of the organic template in a nitrogen gas flow at 400°
C. converts it to a carbonaceous substance mainly through hydrogen
release by decomposition of the organic template; and the calcination in
an oxygen gas flow at 550° C. removes the organic template through
oxidation (combustion) of the carbonaceous substance. Conducting such
two-stage calcination is considered to be able to more effectively
eliminate an influence of steaming by steam generated by combustion of
the organic template than the case of direct calcination in an oxygen gas
flow.

[0122]The respective calcined ZSM-22 were cooled to room temperature, and
thereafter each was transferred to a flask; and a 0.5N ammonium chloride
aqueous solution was added thereto, and refluxed overnight under heating
to ion-exchange the ZSM-22. After the finish of the ion-exchange,
respective solid contents were sampled by filtration, washed with
ion-exchange water, and dried overnight in a drier at 60° C. to
obtain respective NH4 type ZSM-22. These ZSM-22 are those
ion-exchanged in the state containing no organic template. Hereinafter,
the respective ion-exchanged NH4 type ZSM-22 obtained as described
above are denoted as "ZSM-22[27]C-IE", "ZSM-22[29]C-IE",
"ZSM-22[31]C-IE", and "ZSM-22[33]C-IE", respectively. Here, C-IE
expresses having been ion-exchanged in the state containing no organic
template by the calcination, and a numeral in [ ] expresses a
hydrothermal synthesis time.

[0123]With respect to each ZSM-22 obtained as described above, the BET
surface area, the external surface area and the pore volume were
quantitatively determined by experiments of nitrogen adsorption at
-196° C. Details of the determination method are as described in
"Experimental Section" in Non-Patent Document 2 shown before. From the
results, "pore volume/external surface area" as an index of judgment on
nanocrystals was calculated. The results are shown in Table 1.

[0124]ZSM-22 of 27 hours in hydrothermal synthesis time has a large
external surface area (132 m2/g) and a small pore volume (0.064
mL/g), which exhibits characteristics of nanocrystals. On the other hand,
ZSM-22 of 29 hours, 31 hours and 33 hours in hydrothermal synthesis time
have small external surface areas (62 to 84 m2/g) and large pore
volumes (0.081 to 0.087 mL/g), which reveals that the aggregation of
nanocrystals has already occurred. That is, the above results indicate
that the aggregation of nanocrystals sharply advances between 27 hours
and 29 hours in hydrothermal synthesis time.

[0125]1-1-4. Making Platinum Carried on ZSM-22, and Molding

[0126]Each of "ZSM-22[27]IE", "ZSM-22[29]IE", "ZSM-22[31]IE",
"ZSM-22[33]IE", "ZSM-22 [27]C-IE", "ZSM-22 [29]C-IE", "ZSM-22[31]C-IE"
and "ZSM-22[33]C-IE" obtained as described above was made to carry
platinum and molded by the following method.

[0127]First, tetramminedichloroplatinum (II) (Pt(NH3)4Cl2)
was dissolved in an amount at minimum of ion-exchange water. The solution
was impregnated in the respective NH4 type ZSM-22 by the incipient
wetness method to make the ZSM-22 carry platinum such that the platinum
amount is 0.3% by mass with respect to the mass of the ZSM-22. Then,
these were dried overnight in a drier at 60° C., and thereafter
molded into a disc shape by tableting molding, and further pulverized and
sieved into amorphous powdery products having a maximum particle size of
125 to 250 μm.

[0128]1-1-5. Activation of Catalysts

[0129]50 mg of each of the platinum-carrying NH4 type ZSM-22 obtained
as described above was filled in a microreactor used for reaction (its
detail will be described later), calcined in an oxygen gas flow at
400° C. for 1 hour, and then subjected to a reduction treatment in
a hydrogen gas flow for 1 hour to activate a catalyst.

[0130]Here, the respective ZSM-22 in which platinum is carried and counter
ions are turned to protons by the activation treatment are denoted as
"Pt/H-ZSM-22[27]IE", "Pt/H-ZSM-22[27]C-IE", and so on.

[0131]1-2. Evaluation of Catalysts by the Isomerization Reaction Using
Normal Decane

[0132]Each catalyst obtained as described above was evaluated for
catalytic characteristics by the isomerization reaction using normal
decane.

[0133]1-2-1. Reaction Apparatus

[0134]The reaction was carried out using a fixed bed type microreactor,
described before, composed of a stainless steel tube of 2.1 mm in inner
diameter and 30 mm in length. 50 mg of a catalyst was filled in the
lowermost part. Oxygen gas and hydrogen gas for activating the catalyst,
nitrogen gas for purging, and a hydrogen gas containing normal decane
vapor as a reaction raw material were changed over by valves, and
supplied to the microreactor. Normal decane as a reaction raw material
was supplied to the microreactor, accompanying the hydrogen gas by
passing the hydrogen gas through a normal decane saturating apparatus
heated at a certain temperature, and the reaction was carried out in a
vapor phase. The reaction product gas was sampled by a sampling valve
which was installed downstream of the microreactor and whose pressure was
controlled, and fed for analysis to a gas chromatographic device (GC)
equipped with a multicapillary column with a stationary phase of
dimethylpolysiloxane.

[0135]1-2-2. Reaction Operations

[0136]In the reaction apparatus described above, with respect to the
activation of a catalyst and the reaction of normal decane, a series of
operations of the gas selection, gas flow rate, reaction temperature,
selection of valves, sampling of a reaction product, the operation of GC
and the like was carried out. The basic operations involve, first,
carrying out the activation treatment of a catalyst at 400° C.,
purging the system by nitrogen gas and varying the microreactor
temperature to 150° C., and thereafter introducing a hydrogen gas
containing normal decane vapor to initiate the isomerization reaction.
The reaction product gas was sampled after 1 hour, and analyzed; the
reaction temperature was varied to 160° C., and after
stabilization for 1 hour, the reaction product gas was again sampled, and
analyzed. Hereafter, the reaction temperature was raised 10° C. by
10° C.; the stabilization and the analysis of the product were
repeated to the reaction temperature of 300° C.

[0137]1-2-3. Reaction Conditions

[0138]The isomerization reaction of normal decane in the presence of
hydrogen was carried out under the following conditions. [0139]Raw
material normal decane: a reagent (purity: 99% or more) was used as it
was. [0140]Reaction pressure: 0.45 MPa [0141]Hydrogen/normal decane
ratio: 375 mol/mol [0142]Reaction temperature: 150 to 300° C.,
temperature rise 10° C. by 10° C.

[0143]1-2-4. Reaction Results

[0144]The results of normal decane conversion (% by mass) and the
C10-isomer yields (% by mass) obtained from the isomerization reaction
described above using normal decane are shown in FIG. 1 and FIG. 2. The
normal decane conversion and the C10-isomer yield are defined by the
formulae shown below.

C10-isomer yield (% by mass)=[C10 isoparaffin total content in a reaction
product (% by mass)]

[0145]FIG. 1(a) is a diagram in which the normal decane conversion (dashed
lines) and the C10-isomer (isodecane) yields (solid lines) are plotted
vs. the reaction temperature for the isomerization reaction of normal
decane using Pt/H-ZSM-22[27]IE (Example 1) and the isomerization reaction
of normal decane using Pt/H-ZSM-22[27]C-IE (Comparative Example 1); and
FIG. 1(b) is a diagram in which the normal decane conversion (dashed
lines) and the C10-isomer (isodecane) yields (solid lines) are plotted
vs. the reaction temperature for the isomerization reaction of normal
decane using Pt/H-ZSM-22[29]IE (Comparative Example 2) and the
isomerization reaction of normal decane using Pt/H-ZSM-22[29]C-IE
(Comparative Example 3). FIG. 2(a) is a diagram in which the normal
decane conversion (dashed lines) and the C10-isomer (isodecane) yields
(solid lines) are plotted vs. the reaction temperature for the
isomerization reaction of normal decane using Pt/H-ZSM-22[31]IE
(Comparative Example 4) and the isomerization reaction of normal decane
using Pt/H-ZSM-22[31]C-IE (Comparative Example 5); and FIG. 2(b) is a
diagram in which the normal decane conversion (dashed lines) and the
C10-isomer (isodecane) yields (solid lines) are plotted vs. the reaction
temperature for the isomerization reaction of normal decane using
Pt/H-ZSM-22[33]IE (Comparative Example 6) and the isomerization reaction
of normal decane using Pt/H-ZSM-22[33]C-IE (Comparative Example 7). In
plots in the Figures, ◯ denotes the reaction using the
catalyst constituted of ZSM-22 by the "IE" treatment; and quadrature
denotes the reaction using the catalyst constituted of ZSM-22 by the
"C-IE" treatment.

[0146]As shown in FIG. 1 and FIG. 2, it is found that the catalyst
constituted of ZSM-22[27]C-IE composed of nanocrystals more decreases in
the activity (the curve of the normal decane conversion shifts to a
higher temperature side) than the catalysts constituted of
ZSM-22[29]C-IE, ZSM-22[31]C-IE and ZSM-22[33]C-IE which are aggregated
crystals of nanocrystals. It is further found that although the catalyst
constituted of the IE-treated ZSM-22 more decreases in the activity than
the catalyst constituted of the C-IE-treated ZSM-22, the former catalyst
improves in the isomerization selectivity and increases in the maximum
value of the C10-isomer yield. This tendency is found in the cases where
ZSM-22 is nanocrystals and also where it is aggregated crystals. Further,
the catalyst (Pt/H-ZSM-22[27]IE) (a catalyst according to Example 1)
constituted of ZSM-22[27]IE composed of nanocrystals exhibits a
C10-isomer yield curve wide with respect to the reaction temperature, and
indicates high isomer yields over a wide reaction temperature.
Particularly in the range where the reaction temperature is high and the
normal decane conversion is high (near 100%), the catalyst is confirmed
to provide a higher C10-isomer yield than the other catalysts (the
catalysts according to Comparative Examples 1 to 7).

Example 2

[0147]2. Manufacture of a Lube-Oil Base Oil by Dewaxing a Wax

[0148]A hydroisomerization catalyst was manufactured by using the
ZSM-22[27]IE obtained as described above as a constituent and molding it
together with a binder; and a wax originated from a petroleum was dewaxed
by the hydroisomerization using the catalyst to manufacture a lube-oil
base oil.

[0149]2-1. Manufacture of a Catalyst

[0150]2-1-1. Manufacture of ZSM-22[27]IE

[0151]ZSM-22[27]IE was prepared as in Example 1.

[0152]2-1-2. Binder Formulation, Molding, and Calcination

[0153]ZSM-22[27]IE and alumina as a binder were formulated in a mass ratio
of ZSM-22[27]IE:alumina of 70:30; and a small amount of ion-exchange
water was added thereto, and the mixture was kneaded, and molded by
extrusion molding to obtain a cylindrical molded product of about 1.5 mm
in diameter and about 5 mm in length. Then, the molded product was
calcined in an air flow at 400° C. for 3 hours.

[0154]2-1-3. Platinum Carrying, and Calcination

[0155]The calcined molded product obtained as described above was
impregnated with an aqueous solution of tetramminedichloroplatinum by the
incipient wetness method to make platinum carried such that the carried
amount of platinum was 0.5% by mass with respect to the mass of
ZSM-22[27]IE. Further, the platinum-carried product was calcined in an
air flow at 400° C. for 3 hours to obtain a hydroisomerization
catalyst.

[0156]2-1-4. Activation of the Catalyst

[0157]100 mL of the hydroisomerization catalyst was filled in a stainless
steel tube of 15 mm in inner diameter and 380 mm in length, and subjected
to a reduction treatment in a hydrogen flow (hydrogen partial pressure: 3
MPa) at an average temperature of the catalyst layer of 350° C.
for 12 hours to activate the catalyst.

[0158]2-2. Manufacture of a Lube-Oil Base Oil by Dewaxing a Wax

[0159]2-2-1. Reaction Apparatus

[0160]A lube-oil base oil was manufactured by dewaxing a wax using a fixed
bed continuous circulation type reaction apparatus equipped with a
reaction tube filled with the activated hydroisomerization catalyst
described above. The reaction apparatus was connected to a gas
chromatograph, which enabled analysis of the product at the outlet of the
reactor.

[0161]2-2-2. Raw Material

[0162]As a wax raw material, a petroleum wax (the carbon number
distribution: C20 to C43) was prepared.

[0163]2-2-3. Reaction Operations

[0164]The wax raw material was fed under the conditions of the reaction
temperature: 200° C., the hydrogen partial pressure: 3 MPa, LHSV:
2.0 h-1, and the hydrogen/oil ratio: 500 NL/L, and the dewaxing was
started by the hydroisomerization reaction. After the reaction for 72
hours, the reaction product was sampled and analyzed. Thereafter, the
reaction temperature was stepwise raised up to 350° C. with the
hydrogen partial pressure, LHSV and the hydrogen/oil ratio as they were,
to increase the feedstock oil conversion. The operations, in which the
reaction was carried out at each reaction temperature for 72 hours, and
at each time when the reaction stabilized, the corresponding reaction
product was sampled and analyzed, and the temperature was raised to the
successive reaction temperature, were repeated.

[0165]As a result of the analysis of the reaction product of the each
reaction temperature, the normal paraffin conversion in the raw material
was 100% at the reaction temperature of 330° C. or more.

[0166]2-2-4. Sampling of Lube-Oil Base Oil Fractions

[0167]The product oil obtained at the reaction temperature of 330°
C. was fractionated into naphtha, kerosene and gas oil fractions, and
other heavy fractions (boiling point: 330° C. or more). No normal
paraffin was detected in the obtained heavy fractions. The heavy
fractions were further fractionated to obtain a lube-oil base oil
fraction having a boiling point range of 330 to 410° C. and a
kinematic viscosity at 100° C. of 2.7±0.1 cSt and a lube-oil
base oil fraction having a boiling point range of 410 to 450° C.
and a kinematic viscosity at 100° C. of 4.0±0.1 cSt. The yields
of both the fractions were, respectively, 30% and 45% to the raw oil. The
fraction having a boiling point range of 410 to 450° C. had a pour
point of -27.5° C. and a viscosity index of 142.

[0168]As described heretofore, it was confirmed that by dewaxing a wax
using a catalyst molded from ZSM-22[27]IE and an alumina binder and
carrying platinum, a high-performance lube-oil base oil was provided with
a high yield.

INDUSTRIAL APPLICABILITY

[0169]The present invention can provide a hydroisomerization catalyst
having a sufficiently low cracking activity of normal paraffins and/or
produced isoparaffins when the normal paraffin conversion is sufficiently
raised, and having a high isomerization selectivity, in
hydroisomerization of hydrocarbon oils containing normal paraffins, and a
method for manufacturing the hydroisomerization catalyst. The present
invention can further provide a dewaxing method of hydrocarbon oils
enabling to provide, stably and with a high yield, hydrocarbon oils
suitable for lube-oil base oils and/or fuel base oils from hydrocarbon
oils containing normal paraffins, and a manufacturing method of lube-oil
base oils enabling to provide, with a high yield, high-performance
lube-oil base oils from hydrocarbon oils containing normal paraffins, by
using the hydroisomerization catalyst.